1. Technical Field
This invention relates to a permanent magnet focused multi-stage depressed collector (MSDC) klystron, and more particularly to a gun-only magnet for use in a MSDC klystron tube.
2. Description of Background Art
Klystron tubes are known devices used for high power transmission of microwave signals. Klystrons are used typically in terrestrial transmission of radio frequency signals, such as for VHF or UHF transmission of radio and television signals. Klystrons also have use in uplink paths in ground to orbiting satellite systems.
There is a continuing effort to make klystron tubes more efficient as well as smaller with the same or increased output power. Heat loss, as well as power loss due to inefficient tube operation, is under continuous scrutiny. Multi-stage depressed collector tubes have been discussed in the prior art. Marrying the MSDC technology in a high power uplink klystron tube has been an unreached goal.
Cost and efficiency are two major factors in the design and manufacture of high power regulator circuits. In addition, maximization of the circuit efficiency increases the value of the circuit. That is, while the circuit components may have a high relative cost, increasing the efficiency of the operation of the circuit offsets the initial cost of the circuit elements from the outset. Thus, a high power supply designer wants to maximize the efficiency of the circuit designed, keeping costs under control, while continuing to meet design criteria.
The present invention relates to a high power output vacuum electron device. The invention includes a cathode for emitting a supply of electrons and an anode for attracting the electrons, with the anode being constructed to allow the electrons to pass through the anode. An RF generator circuit in the path of the electron beam generates RF signal energy in the presence of a high voltage power source. A magnet surrounds the anode and the RF generation circuit for focusing the electrons into a collimated beam. A collector receives the collimated electron beam and returns the collected electrons to the cathode. The collector is a multi-stage depressed collector, which is shielded from the magnetic field from the magnet. The region of the collector is free of any magnetic fields so that the electron beam naturally disperses to evenly deposit the electrons on the inner walls of the collector. Another embodiment of the invention relates to a gun only magnet for use in a multi-stage depressed collector in a high-energy electron device. A first pole piece of the magnet generates magnetic flux adjacent a cathode of the vacuum electron device to drive and initially focus electrons emitted from the cathode. A second pole piece region of the magnet forms magnetic flux along the path of electrons to focus the electrons into a narrow beam, the magnet having no pole piece in the region of the vacuum electron device where the electrons are collected and returned to the cathode.